1. Field of the Invention
The present invention is directed to an apparatus for installing a curved mirror used in a scanning optical system.
2. Description of Related Art
Some conventional scanning optical systems such as a writing optical system (e.g., a laser beam printer or a laser facsimile) or a reading optical system (e.g., a image scanner) are provided with a curved mirror having a similar structure of a curved mirror 30 shown in FIG. 4. The curved mirror 30 has a curved reflecting surface 31.
The curved mirror 30 is normally made of a synthetic resin. For this reason, the curved mirror 30 tends to change its shape due to the variation of temperature and/or humidity, and/or an external force applied thereto upon being fixed to an optical system (not shown).
When the curved mirror 30 is fixed to an optical system, surfaces 32 located at both end portions of the reflecting surface 31 are used as reference surfaces for positioning the curved mirror 30 with respect to the optical system. Since only the surfaces 32 can be used reference surface for positioning, it is difficult for the curved mirror 30 to be fixed to the optical system in a stable manner. Besides, there are limited ways in which to fix the curved mirror 30 to an optical system.
Furthermore, due to the shape of the curved mirror 30 as shown in FIG. 4, there is a high probability that the person in charge of the installation of the curved mirror 30 may accidentally touches the reflecting surface 31, so that the reflecting surface 31 would be degraded or damaged.